Surface Flow Visualization via Tuft-Tracking on Transonic Truss-Braced Wing Configuration

A wind tunnel test of the NASA-Boeing 4% full span Subsonic Ultra Green Aircraft Research (SUGAR) Transonic Truss-Braced Wing (TTBW) was conducted at the 12-Foot Low-Speed Tunnel (12-Ft LST) at NASA Langley Research Center (LaRC). The test aimed to understand flight behavior of TTBW configurations at edge-of-envelope stall/post-stall conditions and to further advance tools to ensure satisfactory aircraft dynamics at high angles of attack. Surface flow visualizations were implemented using strips of tufts along areas of interest. Improvements on traditional qualitative assessment of tuft videos at various flow conditions are presented to identify separated regions on the aircraft body. Computational Fluid Dynamics (CFD) simulations were performed for selective cases to compare with the qualitative tuft analysis. The qualitative enhancement tuft-flow techniques prove to be useful for non-optimal lighting conditions that arise in a wind tunnel environment and show agreement with CFD results.